画布视图框窗口内的可单击对象或形状

编程问答 2022-08-11

问题描述

<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>

<style>
body {
  font-family: "Lato",sans-serif;
}

.sidenav {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}

.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
  transition: 0.3s;
}

.sidenav a:hover {
  color: #f1f1f1;
}

.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}

#main {
  transition: margin-left .5s;
  padding: 16px;
}

@media screen and (max-height: 450px) {
  .sidenav {padding-top: 15px;}
  .sidenav a {font-size: 18px;}
}
</style>
</head>
<body>

<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a> 
  <a href="#">About</a>
  <a href="#">Services</a>
  <a href="#">Clients</a>
  <a href="#">Contact</a>
    
</div>
<div id="main">
  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; Menu</span>
<canvas id="canvas" width="600" height="350" style="border:2px solid #d3d3d3;">></canvas>
</div>

<script>

var zoomIntensity = 0.1;
var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");
var width = 90;
var height = 50;
var scale = 1;
var originx = 0;
var originy = 0;
var visibleWidth = width;
var visibleHeight = height;


var c = document.getElementById("canvas");
var ctx = c.getContext("2d");

function draw(){

    context.fillStyle = "white";
    context.fillRect(originx,originy,1000/scale,800/scale);

    context.fillStyle = "blue";
    context.fillRect(170,50,50);
    context.fillStyle = "white";
    context.fillText('click here',175,70);   
}

setInterval(draw,1000/60);
canvas.onwheel = function (event){
    event.preventDefault();
    var mousex = event.clientX - canvas.offsetLeft;
    var mousey = event.clientY - canvas.offsetTop;
    var wheel = event.deltaY < 0 ? 1 : -1;
    var zoom = Math.exp(wheel*zoomIntensity);
    
    context.translate(originx,originy);
    originx -= mousex/(scale*zoom) - mousex/scale;
    originy -= mousey/(scale*zoom) - mousey/scale;
    context.scale(zoom,zoom);
    context.translate(-originx,-originy);
    scale *= zoom;
    visibleWidth = width / scale;
    visibleHeight = height / scale;
}
function openNav() {
  document.getElementById("mySidenav").style.width = "200px";
  document.getElementById("main").style.marginLeft = "200px";
}

function closeNav() {
  document.getElementById("mySidenav").style.width = "0";
  document.getElementById("main").style.marginLeft= "0";
}
</script>

</body>
</html>
即使在放大或缩小时，

仍然可以在画布框架或视图框上使形状或对象可单击，因为我看到的所有示例只是一个固定的可单击位置。例如，当我放大时，谷歌地图位置可以单击更多对象。 有没有办法使形状或对象在画布框架或视图框上可单击，即使当我放大或缩小时，由于我看到的所有示例只是一个固定的可单击位置。例如，当我放大时，谷歌地图位置可以单击更多对象。

解决方法

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